21221137369 has 2 divisors, whose sum is σ = 21221137370. Its totient is φ = 21221137368.

The previous prime is 21221137351. The next prime is 21221137391. The reversal of 21221137369 is 96373112212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13738887369 + 7482250000 = 117213^2 + 86500^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221137369 - 2⁵ = 21221137337 is a prime.

It is a super-2 number, since 2×21221137369² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21221137309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610568684 + 10610568685.

It is an arithmetic number, because the mean of its divisors is an integer number (10610568685).

Almost surely, 2^21221137369 is an apocalyptic number.

It is an amenable number.

21221137369 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221137369 is an equidigital number, since it uses as much as digits as its factorization.

21221137369 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 37.

The spelling of 21221137369 in words is "twenty-one billion, two hundred twenty-one million, one hundred thirty-seven thousand, three hundred sixty-nine".